CheckboxType Field

Creates a single input checkbox. This should always be used for a field
that has a boolean value: if the box is checked, the field will be set to
true, if the box is unchecked, the value will be set to false.

This option determines what value the field will return when the placeholder
choice is selected. In the checkbox and the radio type, the value of empty_data
is overriden by the value returned by the data transformer (see How to Use Data Transformers).

When you create a form, each field initially displays the value of the
corresponding property of the form's domain data (e.g. if you bind an object to
the form). If you want to override this initial value for the form or
an individual field, you can set it in the data option:

The data option always overrides the value taken from the domain data
(object) when rendering. This means the object value is also overriden when
the form edits an already persisted object, causing it to lose its
persisted value when the form is submitted.

If true, any errors for this field will be passed to the parent field
or form. For example, if set to true on a normal field, any errors for
that field will be attached to the main form, not to the specific field.

Imagine you have a custom method named matchingCityAndZipCode() that validates
whether the city and zip code match. Unfortunately, there is no "matchingCityAndZipCode"
field in your form, so all that Symfony can do is display the error on top
of the form.

With customized error mapping, you can do better: map the error to the city
field so that it displays above it:

If the violation is generated on a property or method of a class, its
path is simply propertyName;

If the violation is generated on an entry of an array or ArrayAccess
object, the property path is [indexName];

You can construct nested property paths by concatenating them, separating
properties by dots. For example: addresses[work].matchingCityAndZipCode;

The right side contains simply the names of fields in the form.

By default, errors for any property that is not mapped will bubble up to the
parent form. You can use the dot (.) on the left side to map errors of all
unmapped properties to a particular field. For instance, to map all these
errors to the city field, use:

Sets the HTML attributes for the <label> element, which will be used
when rendering the label for the field. It's an associative array with HTML
attribute as a key. This attributes can also be directly set inside the
template:

Configures the string used as the label of the field, in case the label
option was not set. This is useful when using
keyword translation messages.

If you're using keyword translation messages as labels, you often end up having
multiple keyword messages for the same label (e.g. profile_address_street,
invoice_address_street). This is because the label is build for each "path"
to a field. To avoid duplicated keyword messages, you can configure the label
format to a static value, like: